The use of loose-fill insulation materials such as cellulose or mineral fiber has historically been quite limited with respect to new building construction. In particular, although loose-fill materials have been applied by open-blow techniques to attics and retrofit sidewalls, efforts to introduce loose-fill materials to new construction sidewall applications have generally been unsuccessful due to the inherent nature of the loose-fill materials not to be self-supporting. Use of loose fill tends to conflict with the scheduling desires for construction. Thus, loose-fill materials have not typically been used in new building construction where it is desired to install the insulation before the wall cavity is closed.
Attempts to make cellulose batts have failed to resolve these and other problems. One reason for that failure is the necessity for factory manufactured batts to be compressed or folded for packaging and transportation to the job site. Cellulose insulating materials lack the resilience necessary to spring back to their intended design thickness. Transportation costs tend to be prohibitive if not compressed, due to the large bulk of such non-resilient batts. If compressed upon shipping, such batts are unacceptable due to the reduction in insulating capability resulting therefrom. Moreover, lack of resilience makes remote sizing to fit abnormally shaped wall cavities particularly troublesome.
The use of sprayed-on cellulosic insulation for open cavity installation is, however, known. For example, U.S. Pat. No. 4,804,695 to Horton describes a wet spray method and composition for producing and installing cellulosic insulation wherein cellulosic insulation is combined with an adhesive and a wetting agent to moisten the material before it is blown into place. When dried, the cellulose adheres to the wall surface and provides substantial insulation thereto. One disadvantage of this method is that it requires a significant drying period between the installation of the spray-on material and the closing of the wall. Because the construction process is more efficient when the wall cavity may be closed as soon as the insulation materials are applied, it would be an advantage to provide cellulosic insulation in a form which did not require post-installation drying, and could be enclosed in the wall immediately upon installation.
Additionally, non-batt methods of providing loose-fill insulation in the wall of the building are known. For example, U.S. Pat. No. 4,385,477 to wails et al. discloses a method and apparatus for placing loose-fill insulation in a structural component wherein the structural component is covered with a retainer barrier layer, a plurality of small entrances in the retainer barrier layer are provided., and loose-fill insulation is installed through those entrances.
U.S. Pat. No. 4,712,347 to Sperber describes an apparatus and method to retain loose-fill insulation between the outer and inner walls of a structure. With the Sperber method, a flexible netting material is placed on the inwardly facing sides of the studs of the wall, one or more access holes are provided in the netting, and particulate insulation is delivered into the enclosed space defined by the outer walls, the studs, and the netting. The Sperber method uses porous netting so that the displaced air may exit through the netting, thereby achieving uniform and efficient compaction of the particulate insulation. The method of Sperber would not, however, be effective with loose-fill cellulose materials. For example, bags of loose fill cellulose are preferably used at a density of approximately 3 lbs./ft.sup.3 to avoid settling of the materials, but the netting of Sperber does not provide adequate structural support to allow such a density. Therefore, the netting of Sperber would sag and bow outwardly if loose fill cellulose were installed at its appropriate density without the use of a supporting surface.
U.S. Pat. No. 4,829,738 to Moss discloses a method of providing loose-fill insulation in the cavity between the studs of a wall under construction by covering the open side of the cavity with a removable pressure plate to substantially enclose the wall cavity. The pressure plate contains at least one aperture, preferably positioned near the top of the pressure plate, through which loose fill insulation may be delivered. After the installation has been installed, the pressure plate is removed and the wall cavity is enclosed by addition of the interior wall surface.
Each of the above described methods require that the loose fill insulation be blown into the wall cavity while workers are present. Unfortunately, particles of loose fill insulation become airborne during this process, and may become inhaled by workers or others at the job site. It would be an advantage if loose fill insulation were contained in a plastic envelope or bag during installation so that it could not escape to the atmosphere.
Prior to the present invention, applicant used augers to fill vertically oriented perforated paper bags with cellulose material at a density appropriate for shipping, which was higher than appropriate for wall insulation. The auger was provided with cellulose through a system similar to that disclosed herein, and having a return air path. In that system, a counterweight was used, but it was attached to a moveable auger which exited from the fixed position vertically oriented bag as the bag was filled.
Other advantages to containing the insulation in plastic envelopes can also be envisioned. In particular, the use of a plastic envelope to contain the loose-fill insulation would avoid problems relating to moisture in the product. No mold or fungus would grow in the insulation if the insulation were protected from moisture and humidity. In addition, the problem of settling would be largely avoided because the cause of settling is known to result in large degree from condensation within the product. Finally, the insulation capability (commonly stated as the R-value of the insulation) would be protected if the insulation does not become moist and clump and/or decay in the framing members.
An additional benefit to using envelopes filled with loose-fill insulation would be the increased ease of handling and ease of installation of the product. The use of envelopes would allow the construction workers to fit the insulation easily around wires, pipes, etc., by simply slitting the back of the bag and bending the back around the obstruction. Even when obstructions are not encountered, the use of insulation batts is known to be particularly simple and fast.
In addition, loose-fill cellulose insulation is known to be an especially effective insulating material. For example, while the R-value of loose-fill fiberglass is known to decrease by more than 50% when used in temperatures of -18.degree. F. or less, the insulation value of loose-fill cellulose may even improve under those harsh conditions.
Finally, loose-fill cellulose insulating material is particularly cost effective, due to the wide availability of both new and used cellulosic materials. Many opportunities to recycle used resources are also available, thereby effecting both cost savings and environmental benefits.
In view of the forgoing, a need exists for a method of providing cellulose insulation in batts which can be easily used in new building construction. The present invention addresses that need.